Authorities examining why tornado sirens didn't sound in Elk Grove, Mount Prospect

An internal review by the Northwest Central Dispatch System is underway to determine why tornado sirens did not sound in Elk Grove Village and parts of Mount Prospect when activated late Sunday night.

Though neither community was struck by the tornado that devastated portions of southern DuPage County, they were among the areas that should have received siren warnings under current procedures, said John Ferraro, executive director of the Arlington Heights-based agency.

The fact that they didn't is part of the agency's full after-event review.

"It needs to be reliable every time," Ferraro said of the tornado warning system.

Northwest Central Dispatch System, which serves 11 communities in the Northwest suburbs, followed standard activation procedures for the relevant sirens when the National Weather Service issued a tornado warning for the area at 10:44 p.m. Sunday.

Elk Grove Village officials announced Tuesday that they too are seeking answers from Northwest Central Dispatch's internal review and exploring the possibility for alert redundancies to ensure the village's six tornado sirens go off when activated.

"While there are several means of notifying residents about oncoming severe weather, many of our residents rely on the air sirens as an indication to seek shelter immediately," Elk Grove Village Mayor Craig Johnson said in a statement. "That system needs to work every time in order for it to be effective. Failure of the system is unacceptable by Elk Grove standards and the system must work 100% of the time to protect our residents to the utmost safety to which they are entitled. We're working with the Northwest Central Dispatch System to determine what went wrong in order to ensure it never happens again!"